3. Researchers at MIT's Computer Science and Artificial
Intelligence Laboratory.
Dina Katabi , a professor in MIT’s Department of
Electrical Engineering and Computer Science, and her
graduate student Fadel Adib.
history
4. Previous attempts to track moving targets through
walls have done so using an array of spaced antennas.
Each capture the signal reflected off a person moving
through the environment.
This would be too expensive and bulky for use in a
handheld device.
So instead Wi-Vi uses just one receiver.
introduction
5. Based on the principle of RADAR and SONAR imaging.
WI-VI is potentially an X-RAY vision created with low
power Wi-Fi signals.
This tech uses reflected Wi-Fi signals to track the
movement of people behind walls.
See through movement behind walls.
basic working
6. RADAR and SONAR work on the Doppler effect.
RADAR is an object detection system which
uses radio waves to determine the range, altitude,
direction, or speed of objects.
Depends on its own transmitted signal.
principle
7. Wi-Vi relies on a simple hardware of 2.4 GHz Wi-Fi
radios.
Wi-Fi signals easily penetrate through walls.
Small enough to be portably used.
Integrated in hand held devices.
8. WI-VI uses two transmitting antennas and a single
receiver.
Transmitting signals are low power Wi-Fi signals.
The two antennas transmit almost identical signals,
except the second antenna's signal is the inverse of
the first, resulting in interference.
How it works?
10. Any static objects that the signals hit including the
wall create identical reflections, they too are cancelled
out by this nulling effect.
Only those reflections that change between the two
signals, such as those from a moving object, arrive
back at the reciever.
12. As the person moves through the room, his or her
distance from the receiver changes, meaning the time
it takes for the reflected signal to make its way back to
the receiver changes.
The system then uses this information to calculate
where the person is at any one time.
13. All reflections from static objects are cancelled out, and the
only thing registered by the device is the moving human.
14.
15. Wi-Vi delivers a more basic perspective on moving
objects.
Relatively low resolution compared to a traditional
camera.
Wi-Vi delivers a more basic perspective on moving
objects. “Simple gestures” are also traceable.
resolution
16.
17. Possible use in smart phones as a hand held WI-VI
device.
Monitoring situations in hospitals or a conspired
heist.
Disaster recovery.
Gaming.
applications
18. Smart hand held device which gives an insight vision
through walls.
Could prove to be very powerful and effective device
for defence purposes.
Possibly the next generation RADAR.
conclusion
